Summary
This study was concerned with the effect of insulin and catecholamines on the rate limiting enzymes of cholesterol metabolism in rat hepatocytes. Insulin was found to increase the activity of 3-hydroxy-3-methyl glutaryl coenzyme A reductase and to have no effect on the activity of acyl-coenzyme A: cholesterol-o-acyltransferase. Noradrenaline and isoprenaline increased the activities of both 3-hydroxy3-methyl glutaryl coenzyme A reductase and acyl-coenzyme A: cholesterol-o-acyltransferase. The effect of noradrenaline or isoprenaline in the presence of insulin was that of a lower stimulatory response on 3-hydroxy-3-methyl glutaryl coenzyme A reductase but comparable to that found with either catecholamine alone. The combination of either catecholamine with insulin had no effect on the activity of acyl-coenzyme A: cholesterol-o-acyltransferase. These observations suggest that the activities of 3-hydroxy-3-methyl glutaryl coenzyme A reductase and acyl-coenzyme A: cholesterol-o-acyltransferase are regulated independently by insulin in the presence or absence of catecholamines. By contrast, catecholamines appear to regulate both enzyme activities in a similar fashion.
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Gibbons GF, Bjomsson OG, Pullinger CR (1984) Evidence that changes in hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity are required partly to maintain a constant rate of sterol synthesis. J Biol Chem 259:14399–14405
Christensen NJ (1978) Catecholamines and Diabetes Mellitus. Diabetologia 16:211–224
Scott LM, Tomkin GH (1982) Cholesterol metabolism in diabetes mellitus in the rat. Diabetologia 23:14 (abstract)
Edwards PA (1975) The influence of catecholamines and cyclic AMP on 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and lipid biosynthesis in isolated rat hepatocytes. Arch Biochem Biophys 170:188–203
Scott LM, Tomkin GH (1982) Changes in hepatic and intestinal cholesterol regulatory enzymes: the influence of metformin. Biochem Pharmacol 32:827–830
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the folin phenol reagent. J Biol Chem 193:265–275
Ingebritsen TS, Geelen MJH, Parker RA, Everson KJ, Gibson DM (1979) Modulation of hydroxymethylglutaryl-CoA reductase activity, reductase kinase activity, and cholesterol synthesis in rat hepatocytes in response to insulin and glucagon. J Biol Chem 254:9986–9989
Oberhaensli RD, Schwendimann R, Keller U (1985) Effect of norepinephrine on ketogenesis, fatty acid oxidation, and esterification in isolated rat hepatocytes. Diabetes 34:774–779
Exton JH (1980) Mechanisms involved in —adrenergic phenomena: role of calcium ions in actions of catecholamines in liver and other tissues. Am J Physiol 238:E3-E12
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Devery, R., Tomkin, G.H. The effect of insulin and catecholamines on the activities of 3-hydroxy-3-methyl glutaryl coenzyme A reductase and acyl-coenzyme A: cholesterol-o-acyltransferase in isolated rat hepatocytes. Diabetologia 29, 122–124 (1986). https://doi.org/10.1007/BF00456123
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DOI: https://doi.org/10.1007/BF00456123